The large amount of liquid water on Earth – possibly delivered early in its life by comets and asteroids – was once thought to be unique.
But now scientists say that Earth-like oceans may be commonplace in the universe, suggesting that life, too, could be more abundant.
Their theory is based around a distant star, which was found to have large amounts of water in its atmosphere.
University of Warwick scientists studied a distant white dwarf star 530 light-years away. Observations revealed huge amounts of water in its atmosphere They suggest this means water-bearing asteroids are common. And it means more planets may have oceans like Earth (illustration of an alien world shown)
The research, led by the University of Warwick, focused on a distant white dwarf star known as SDSS J1242+5226, which is 530 light-years away in the Ursa Major constellation.
Based on readings, it appears that the star has about 30 to 35 per cent of the water found in Earth’s oceans.
The scientists believe this was delivered to the star by a large asteroid, similar in size to Ceres in our own solar system, about 560 miles (900km) across.
The implications are that water-bearing asteroids like this might be common.
‘Our research has found that, rather than being unique, water-rich asteroids similar to those found in our solar system appear to be frequent,’ said astronomer Dr Robert Raddi, from the University of Warwick.
‘Accordingly, many planets may have contained a volume of water, comparable to that contained in the Earth.’
The research also supports the view that Earth was initially dry, with its oceans being delivered by water-rich comets or asteroids.
To come to their conclusion, the scientists used the William Herschel Telescope in the Canary Islands to detect a large amount of hydrogen and oxygen – the constituents of water – in the atmosphere of the white dwarf, the compact remnant of a sun-like star.
‘Our research has found that, rather than being unique, water-rich asteroids [illustrated[ similar to those found in our solar system appear to be frequent,’ said astronomer Dr Robert Raddi, from the University of Warwick. ‘Many planets may have contained a volume of water, comparable to that contained in the Earth’
The research focused on a distant white dwarf star (illustrated right) known as SDSS J1242+5226, in the Ursa Major constellation. The scientists believe this was delivered to the star by a large asteroid, similar in size to Ceres (shown left) in our own solar system, about 560 miles (900km) across.
Water, water, everywhere? Oceans on Earth were once thought to be unique to our planet – but now it may transpire that many other worlds are habitable, just ours
‘Oxygen, which is a relatively heavy element, will sink deep down over time, and hence a while after the disruption event is over, it will no longer be visible,’ said co-author Dr Boris Gansicke, also from the University of Warwick.
‘In contrast, hydrogen is the lightest element; it will always remain floating near the surface of the white dwarf where it can easily be detected.
‘There are many white dwarfs that hold large amounts of hydrogen in their atmospheres, and this new study suggests that this is evidence that water-rich asteroids or comets are common around other stars than the sun.’
Water is regarded as an essential pre-requisite for Earth-like life.
Many planets have been identified that occupy ‘habitable’ orbital paths around their parent stars where temperatures are mild enough for liquid surface water to exist.
But how many of them actually possess water remains unknown – although this latest theory suggests it might be more common than we thought.
The findings appear in the journal Monthly Notices of the Royal Astronomical Society.
To come to their conclusion, the scientists used the William Herschel Telescope (pictured) in the Canary Islands to detect a large amount of hydrogen and oxygen – the constituents of water – in the atmosphere of a white dwarf, the compact remnant of a sun-like star
